The present invention relates to a closure member for an opening disposed near the lower end of the cooling chamber of a continuous casting system or the like, which opening serves for the passage of a railbound carriage which moves parallel to the cast material and is provided for the purpose of maintenance.
During casting of steel in the form of a band or strip, hardening of the steel strip along one part of the strip guiding rack is enhanced by spraying large quantities of water onto it from spraying nozzles. In addition to the strip, strip guiding rollers which are in direct contact with the surface of the strip are cooled as well. In order to shield this so-called wet region from the lower portion of the guiding rack, where the guide rollers are cooled from the inside, and to protect this part against moisture and steam, a so-called cooling chamber is employed which must be provided with a closable opening so that maintenance work, such as the exchange of driving frames and guide roller segments, can be performed.
It is known to keep these openings closed during the casting process by means of wing, drop, sliding or rolling gates. These types of closure members are installed in casting systems in which the driving frames and guide roller segments are installed and are removed by means to bridge cranes which are disposed beneath the pouring platform and moved in a direction transverse to the casting direction, as well as in systems in which the driving frames and guide roller segments are exchanged by means of carriages equipped with driving frame and segment exchanging devices which move on rails parallel to the length of the steel strip.
While the known wing and sliding gates are generally used in conjunction with bridge cranes and are then generally opened and closed manually, rolling gates as well as drop or drop and fold gates, which are generally used in conjunction with the movable carriage equipped with the driving frame and segment exchange devices, are usually opened and closed by electromechanical or hydromechanical drives.
The known closure members have the drawback that they can not always create tight seals due to uneven contact with the surfaces intended for this purpose. The associated sealing devices are therefore usually very complicated and and expensive. Sealing is particularly difficult in the region of the rails for the maintenance carriage. Thus sealing of this region with the known drop or drop and fold gates requires special, manually actuated, small wing gates.